If you told the truth on an earlier poly you had better hope that the two agencies do not share information.  Your current lie could be unmasked if they do share information landing you in the same boat you already sail.  If POST (or other like agency, board, etc.) discovers your lie in the future you will most certainly have your certification revoked.  Not trying to be negative but this is a very real possibilty.  Besides, if you truly do not qualify, you should not get the position regardless of being honest or deceitful.  Integrity is a demand for law enforcement.

To answer you cms questions:  Do not augment any responses when being asked irrelevants.  CMs are for the controls an example of which you provided: "have you ever lied to someone in authority."

Well that certainly explains a bit more.  Do you mind mentioning your current age?  That may have been a factor also.

I do agree that experimentation while a minor should be regarded as youthful indescretion.  I have a stern eye turned on me because of marijuana usage when I was 13 & 14 years old.  That has been 16 years ago but it still counts against me.

Again bear in mind that LEA's share applicant information.  Your former admission could jump up and bite you.

leo123456,

Are you applying for a law enforcement job?  

If you are I would recommend you tell the truth up front.  Tell you background investigator about your use of MDMA.  If he DQ’s you, so be it.  That is vastly preferable to starting off your police career with a lie.  

Some agencies will DQ you for a single tab of MDMA, others will not.  For the ones that will not they usually look to see if you have a span of five to seven years from the time you used the drug.  During that time they want to see a clean college/employment/military record.  Be honest and keep trying until you find an agency that will take you.  Dishonesty is a form of corruption and you can’t be a slightly corrupt cop.  You are either corrupt or you aren’t – there are no degrees.

I realize that you may have read material on this site and come to the conclusion that the information provided here is intended to allow people to “pass” a polygraph even when they are lying, but it’s not.  In my opinion, the information on how to beat the polygraph is provided so that honest people can protect themselves from a false positive.  There just isn’t any realistic way of providing that information solely to truthful people, so it is made available to everyone.

You chose to ingest an illegal drug.  Now man up and live with the consequences.  If that means you can’t become a cop just yet, so be it.  If it means you can never become a cop, then deal with that in a way that doesn’t include lying about your past.

Sometimes personal responsibility sucks.